Fill in the blanks - bug?

hello,

can anyone confirm that fill in the blanks works for a retry after the first incorrect answer?
After filling in some wrong text one cannot enter a second time as retry.
Please check here, third question for direct navigation.
https://h5p.org/node/711353

Behaviour Settings:
enable retry 
put filed on seperate lines

Adaptivity:
Require full score for task before proceeding

any ideas how to get h5p accept the second, third, ... try?

regards,
oliver